Acute histologic effects and thermal distribution profile of disc biacuplasty using a novel water-cooled bipolar electrode system in an in vivo porcine model

The Use of Radiofrequency in the Treatment of Pelvic Pain

Radiofrequency ablation (RFA) is a procedure in which radio waves are used to destroy abnormal or dysfunctional tissue. It has been an increasingly utilized treatment option for a variety of medical conditions, such as chronic pain, wherein sensory nerves are targeted and ablated, eliminating their ability to transmit pain signals to the brain. There is a lack of clarity regarding the indications, technique, and efficacy of RFA for chronic pelvic pain. This article reviews recent literature and discusses these topics, including adverse events for different pelvic ablation and pulsed radiofrequency treatment of chronic pelvic pain.

Temperature Distributions of the Lumbar Intervertebral Disc during Laser Annuloplasty : A Cadaveric Study

Objective

Low back pain, caused intervertebral disc degeneration has been treated by thermal annuloplasty procedure, which is a non-surgical treatement. The theoretical backgrounds of the annuloplasty are thermal destruct of nociceptor and denaturization of collagen fiber to induce contraction, to shrink annulus and thus enhancing stability. This study is about temperature and its distribution during thermal annuloplasty using 1414 nm Nd : YAG laser.

Methods

Thermal annuloplasty was performed on fresh human cadaveric lumbar spine with 20 intact intervertebral discs in a 37℃ circulating water bath using newly developed 1414 nm Nd : YAG laser. Five thermocouples were attached to different locations on the disc, and at the same time, temperature during annuloplasty was measured and analyzed.

Results

Thermal probe's temperature was higher in locations closer to laser fiber tip and on lateral locations, rather than the in depth locations. In accordance with the laser fiber tip and the depth, temperatures above 45.0℃ was measured in 3.0 mm depth which trigger nociceptive ablation in 16 levels (80%), in accordance with the laser fiber end tip and laterality, every measurement had above 45.0℃, and also was measured temperature over 60.0℃, which can trigger collagen denaturation at 16 levels (80%).

Conclusion

When thermal annuloplasty is needed in a selective lesion, annuloplasty using a 1414 nm Nd : YAG laser can be one of the treatment options.

In vivo effects of radiofrequency ablation on long bones and the repair process in swine models

PURPOSE

To investigate in vivo effect of radiofrequency ablation (RFA) on swine long bones and the repair process.

MATERIALS AND METHODS

RFA was performed in six swine at the end and middle part of the tibia or femur. After RFA, radiological examinations were performed, and the swine were killed immediately and at different time points post-RFA for histopathological examination.

RESULTS

All swine had successful RFA. The RFA-induced elliptical necrotic area ranged from 3.81-5.24 cm² (mean 4.08 ± 0.73 cm²) at the bone end but 5.60-8.98 cm² (mean 7.58 ± 1.41) at the middle part immediately after RFA until 10 days, with the necrosis area significantly smaller (P = 0.000) at the end than at the middle. RFA only damaged the cortical bone slightly (0.01 cm thick) with no damage to the soft tissues outside the compact bone at both the end and middle. Surrounding the elliptic pale zone of coagulative necrosis was a narrow brown band of hemorrhage and inflammatory exudate. From day 10 until week 12, tissue proliferation and repair became increasingly apparent, with proliferated granulation, fibrous tissue, and fresh and mature bone trabecula.

CONCLUSION

RFA can quickly and effectively destroy the cancellous bone tissue without affecting the cortical bone and activate bone remodeling.

Structural Preservation Percutaneous Endoscopic Lumbar Interlaminar Discectomy for L5-S1 Herniated Nucleus Pulposus

Objective. Structures such as ligamentum flavum, annulus, and lamina play an important role in the segmental function. We proposed the surgical technique for achieving the sufficient preservation of segmental structures, in spite of sufficient removal of pathologic disc in the L5-S1 using the ligamentum flavum splitting and sealing technique. Methods. We retrospectively analyzed 80 cases that underwent percutaneous endoscopic lumbar discectomy for L5-S1 herniated nucleus pulposus, using the ligamentum flavum splitting and sealing technique between January 2011 and June 2013. Outcomes were assessed using VAS (leg, back), MacNab's criteria, and the immediate postoperative MRI for all patients. Structural preservation was classified as complete, sufficient, and incomplete. Results. The surgical results are as follows: 65 cases were complete, 15 cases were sufficient, and 0 cases were incomplete. The VAS was decreased at the last follow-up (leg: from 7.91 ± 0.73 to 1.15 ± 0.62; back: from 5.15 ± 0.71 to 1.19 ± 0.75). A favorable outcome (excellent or good outcome by MacNab's criteria) was achieved in 77 patients (96.25%). During the follow-up period, 2 cases (2.5%) of recurrence have occurred. Conclusion. According to the result, we could obtain the favorable clinical and radiological outcomes while simultaneously removing pathologic discs using the ligamentum flavum splitting and annular fissure sealing technique.

A Prospective, Randomized, Multicenter, Open-label Clinical Trial Comparing Intradiscal Biacuplasty to Conventional Medical Management for Discogenic Lumbar Back Pain

STUDY DESIGN

This study was a prospective, randomized, crossover, multicenter trial for the evaluation of comparative effectiveness of intradiscal biacuplasty (IDB) versus conventional medical management (CMM) in the treatment of lumbar discogenic pain.

OBJECTIVE

The objective was to demonstrate the superiority of IDB over CMM in the treatment of discogenic pain with respect to the primary outcome measure.

SUMMARY OF BACKGROUND DATA

Current therapeutic options for the treatment of chronic low back pain of discogenic origin are limited. CMM is often unsatisfactory with regard to the treatment of discogenic pain. IDB offers a minimally invasive treatment that has been demonstrated to be superior to placebo in the past.

METHODS

A total of 63 subjects with lumbar discogenic pain diagnosed via provocation discography were randomized to IDB + CMM (n = 29) or CMM-alone (n = 34). At 6 months, patients in the CMM-alone group were eligible for crossover if desired. The primary outcome measure was the change in visual analog scale (VAS) from baseline to 6 months. Secondary outcome measures included treatment "responders," defined as the proportion of subjects with a 2-point or 30% decrease in VAS scores. Other secondary measures included changes from baseline to 6 months in (1) short form (SF) 36-physical functioning, (2) Oswestry Disability Index, (3) Beck Depression Inventory, (4) Patient Global Impression of Change, (5) EQ-5D VAS, and (6) back pain-related medication usage.

RESULTS

In the IDB cohort, the mean VAS score reduction exceeded that in the CMM cohort (-2.4 vs. -0.56; P = 0.02), and the proportion of treatment responders was substantially greater (50% vs. 18%). Differences in secondary measures favored IDB. No differences in opioid utilization were noted between groups.

CONCLUSION

Superior performance of IDB with respect to all study outcomes suggests that it is a more effective treatment for discogenic pain than CMM-alone.

LEVEL OF EVIDENCE

2.

Water-cooled radiofrequency neuroablation for sacroiliac joint dysfunctional pain

Sacroiliac (SI) joint dysfunction is a common source of chronic low-back pain. Recent evidences from different parts of the world suggest that cooled radiofrequency (RF) neuroablation of sacral nerves supplying SI joints has superior pain alleviating properties than available existing treatment options for SI joint dysfunctional pain. A 35-year-old male had intractable bilateral SI joint pain (numeric rating scale [NRS] – 9/10) with poor treatment response to intra-articular steroid therapy. Bilateral water cooled = RF was applied for neuroablation of nerves supplying both SI joints. Postprocedure pain intensity was 5/10 and after 7 days it was 2/10. On 18^th-month follow-up, he is pain free except for mild pain (NRS 2/10) on occasional extreme twisting of the back. This case attempts to highlight that sacral neuroablation based on cooled RF technique can be a long lasting remedial option for chronic SI joint pain unresponsive to conventional treatment.

Mechanisms of intervertebral disk degeneration/injury and pain: a review

Degeneration of the intervertebral disk and its treatments are currently intensely investigated topics. Back pain is a condition whose chronic and debilitating nature combined with its prevalence make it a major health issue of substantial socioeconomic importance. Although researchers, and even sometimes clinicians, focus on the degenerated disk as the problem, to most patients, pain is the factor that limits their function and impacts their well-being. The purpose of this review is to delineate the changes associated with disk degeneration and to outline mechanisms by which they could be the source of back pain. Although the healthy disk is only innervated in the external layer of its annulus fibrosus, adjacent structures are plentiful with nociceptive receptors. Stimulation of such structures as a consequence of processes initiated by disk degeneration is explored. The concept of discogenic pain and possible mechanisms such as neoinnervation and solute transport are discussed. Finally, how such pain mechanisms may relate to current and proposed treatment strategies is discussed.

Water-cooled radiofrequency: a neuroablative or a neuromodulatory modality with broader applications?

We report the successful use of water-cooled radiofrequency where more traditional forms of neuroablation—conventional and pulsed radiofrequency—had failed to achieve adequate pain relief. We also discuss the mechanism of neural damage with water cooled radiofrequency and discuss why this technique may have a broader role in the management of a wide array of pain syndromes.

Bipolar radiofrequency lesion geometry: implications for palisade treatment of sacroiliac joint pain

Ex vivo photographic temperature mapping of bipolar radiofrequency (RF) lesions in animal tissue is performed over a wide range of electrode tip spacings, tip lengths, tip diameters, tip temperatures, and lesion times. In vivo temperature measurements collected during clinical treatment of sacroiliac joint (SIJ) pain corroborate those collected ex vivo. Generation of a "strip lesion" connecting two separated bipolar electrode tips is demonstrated ex vivo for tip spacings as large as 20 mm. A rounded rectangular bipolar lesion with midline dimensions 12 mm × 15 mm × 8 mm (L × W × D) is demonstrated using 10 mm parallel tip spacing, 10 mm tip lengths, 20 gauge cannulae, 90°C tip temperature, and 3-minute lesion time. Lesion length can be increased to 18 mm by using 15 mm tip lengths. Lesion width can be increased to 17 mm by using 12 mm tip spacing. The size of conventional bipolar lesions can exceed the size of lesions produced both by conventional monopolar RF (12 mm × 7 mm × 7 mm ellipsoidal) and by cooled monopolar RF as used in spinal pain management (10 mm × 10 mm × 10 mm spherical). SIJ pain is treated by placing 5 to 7 straight RF cannulae perpendicular to the dorsal sacrum and producing 4 to 6 overlapping bipolar RF lesions between the dorsal sacral foramina and the ipsilateral SIJ. This bipolar "palisade" (a defensive fence) creates a continuous lesion spanning the region through which multiple sacral lateral branch nerves travel along irregular, branching paths to reach the SIJ.

Thermal phantom of the intervertebral disc for evaluating intradiscal electrothermal therapies

STUDY DESIGN

a silicone material was evaluated as an intervertebral disc thermal phantom. Temperature mapping was performed during the intradiscal electrothermal therapy (IDET) procedure and compared with results from the cadaver studies.

OBJECTIVE

to determine whether a silicone material can be used as an intervertebral disc thermal phantom for evaluating thermal distributions of intradiscal electrothermal therapies and for reducing the need for cadaver and animal studies.

SUMMARY OF BACKGROUND DATA

studies mapping thermal profiles of intradiscal heating therapies have been performed in cadavers and animal models. These studies are expensive, require special facilities and institutional reviews, and are susceptible to intercadaver and/or interanimal variation. A search of published data yielded no proposed thermal phantoms of the intervertebral disc. METHODS.: The thermal conductivity of a silicone material was measured and compared with that of an intervertebral disc. Thermal distributions were mapped in the material during the IDET procedure and compared with the distributions seen in cadaver studies. Logarithmic regression was performed to predict temperatures at certain distances from the IDET catheter. Mapping and regression were also performed for a decompression catheter.

RESULTS

the thermal conductivity of the silicone material, 0.587 W/m · °C, was similar to that previously reported for the intervertebral disc, 0.595 W/m · °C. Thermal distributions during the IDET procedure were comparable with those seen in previous cadaver studies. Logarithmic regression analysis predicted temperatures greater than 42°C and 60°C at distances of 14.10 and 2.31 mm, respectively, for the IDET catheter. These distances were 12.98 and 3.30 mm, respectively, for the decompression catheter.

CONCLUSION

the silicone material has a thermal conductivity similar to that of intervertebral disc. Temperature distributions in the material during IDET treatment are similar to that seen in cadaver studies. The material provides an alternative to cadaver and animal studies when determining thermal distributions of intradiscal electrothermal therapies.

Radiofrequency treatment in chronic pain

Chronic pain management physicians and patients are always looking for long-term solutions rather than short-lived interventions. There are three main nonsurgical modalities to ablate nervous system elements. These involve the use of extreme cold (cryoablation), high temperature radiofrequency and chemical neurolysis, such as alcohol or phenol. Radiofrequency ablation offers the advantage of being precise, reproducible and effective to a great extent. It also has the ability to stimulate before the ablation to avoid ablating the wrong nerve elements, which provides a considerable safety margin. In this article we will review the basis of radiofrequency ablation and some of the most common applications in the management of chronic pain.